SL-10093: Client code to support experiences changing an environment.  Handle generic messages with "commands" to be executed.

Fix class 1 and 2 transport/gamma funcs and made usage consistent across all shaders.

Fix class1\environment\waterV reverting to old d1/d2 names for wave directions.

Eliminate 20+ callsites with copy-paste of getPosition and/or getNorm code.

Make pipeline use getShadowTarget/releaseShadowTarget consistently.

Also fix terrain response to atmospherics shaders (was failing to apply ambient on low end even when atmospherics was on).

SL-9806 stop rendering stars post deferred so they can be depth sorted properly with clouds and heavenly bodies.

SL-9886: Viewer send and receive new day_name(s) information in the environment protocol for viewer specified names on individual tracks.

Make shaders use consistent naming and parameter order for transport and atmospheric helpers.

Share transport and gamma correction code where possible.

Add lots of asserts and other validation for when things don't go as planned.

Engage dumpShaderSource to get more source output with shader compilation fail.

SL-9905 FIXED [EEP] Teleporting from EEP Region with parcel environment does not clear on non-eep region.

SL-9976 change moon blend/brightness handling in shaders and cleanup extraneous GL state management.

Port over transport, gamma, atmospherics shader stub updates for per-fragment atmospherics.

Fix bindings of current/next noise map when current and next are the same (select only one and force blend factor to 0).

SL-9973

SL-9922 FIXED [EEP] The Day environment settings are changed when open the Water setting in ‘Fixed Environment’ editor

Get dome rendering to not assert the depth test state behind deferred render's back.

Make clouds write and test depth to give stars something to depth test against.

Add z-bias in star vert shader to force some depth testing of stars against clouds.

SL-9911 FIXED [EEP] Day Settings are modifiable in About Land floater for parcel that uses Region Settings

Remove (unused) fan buffer and fix parameterization of the strip vert buffer(s)
to not include a sharp discontinuity at the horizon.

De-hackify WL additive to get better match between ALM and non-ALM rendering
without bringing back SL-1491 lens flare bug.

Replace WL atmospherics sun color calcs, fix water specular sunlight contribution to use them,
and do not add moon contribution during daytime.